Domnick Hunter Maxigas 104, Руководство по обслуживанию

Страница: 24 / 36

24
3.5 Oxygen Analyser Calibration
The frequency of calibration is dependent on how critical the
quality of gas is to the end process and on the customer’s own
internal procedures. However, it is recommended that the
analyser be calibrated at least every 3 months.
The calibration method will depend on whether the generator is a
% or ppm generator and if calibration is to be carried out against
a calibration gas supply or against an independent analyser.
If calibrating the generator against a regulated gas
supply, connect the gas supply to the O
2
Analyser
calibration port on the side of the generator. It is
recommended that the calibration gas used be as close
as possible to the production gas purity. Do not exceed
7barg pressure.
If calibrating the generator against air (% generators
only) leave the O
2
Analyser calibration port open.
If calibrating against an independent analyser connect
the analyser to the nitrogen outlet port of the generator.
Locate the calibration ball valve inside of the shroud and rotate
the handle clockwise so that it is pointing upwards as shown (not
applicable if calibrating the generator against and independent
analyser).
Wait until the O2 reading is stable on the controller.
Note: Depending upon the generator purity and the amount
of residual oxygen it may take an hour or more to stabilise.
Select menu 3.1 and enable the O2 Alarm Over-ride.
Select menu 3.2
The current reading from the 02 analyser will be displayed on the controller.
Using the and keys enter the calibration gas level on the display.
If calibrating a % Generator against air enter the value 20.9%
If calibrating against an independent analyser enter the value of the purity reading from the
independent analyser.
Press to send the calibration level to the O2 analyser.
On successful completion of the calibration the new O2 reading will be shown on the bottom line of
the display.
If the calibration is not successful the original reading from the analyser will be loaded. Should this
occur repeat the above steps.
On completion of the calibration, return the calibration ball valve back to its original position and
remove the regulated calibration gas supply or independent analyser as applicable.
Disable the O2 Alarm Over-ride.
When returning to the main operating menu, “CAL” will be shown on the top line of the display. This
will remain for a period of twenty minutes after the calibration. Throughout this time period the O2
alarm is overridden, to allow the sensor to return to the required level.